1. Field of the Invention
This invention relates to a vibration switch, more particularly to a vibration switch with an optoelectronic sensor member which is controlled by the displacement of a light-transmission rollable member to place two electric contact terminals in one of switch-on and switch-off states.
2. Description of the Related Art
Referring to FIG. 1, a conventional vibration switch 1 is shown to include an insulating housing 11 with an accommodation chamber 111 formed therein for receiving an electric conductive ball member 14. A pair of electric contact terminals 12,13 have upper ends 121,131 which are received in the accommodation chamber 111, and lower ends 122,132 which are disposed outwardly and downwardly of the housing 11. When the housing 11 is in an upright state shown in FIG. 1, the ball member 14 contacts the upper ends 121,131 of the terminals 12,13 to place the terminals 12,13 in a switch-on state. Once the housing 11 is tilted or vibrated, the ball member 14 is moved to disengage the upper ends 121,131, thereby placing the terminals 12,13 in a switch-off state. However, when the vibration switch 1 is used in a moist place, the ball member 14 is liable to oxidize, thereby resulting in unstable electrical connection between the terminals 12,13.
The object of the present invention is to provide a vibration switch which can provide a stable electrical connection between two electric contact terminals.
According to this invention, the vibration switch includes an insulating housing which is adapted to be mounted on a support in an upright direction, and which includes an inner wall that confines an accommodation chamber therein. An optoelectronic sensor member is secured to the housing, and includes light emitting and receiving units which are disposed opposite to each other in a transverse direction relative to the upright direction. The light emitting and receiving units respectively define a light emitting path and a light receiving path which extend through the inner wall and into the accommodation chamber to cooperatively establish a light beam route for passage of a light beam that is emitted from the light emitting unit and that is received by the receiving unit. Two electric contact terminals are respectively and electrically connected to the light receiving unit, and extend downwardly and outwardly of the housing so as to be adapted to be connected electrically to the support. A rollable member is made from a light-transmission material, and is rollable in the accommodation chamber between a rest position, where the rollable member is disposed on the light beam route with a first orientation so as to interfere with the light beam, such that the resultant light beam received by the receiving unit has a first light intensity, and where the insulating housing is in a stable position, and a labile position, where, due to a jerking force acting on the insulating housing, the rollable member is disposed on the light beam route, with a second orientation so as to interfere the light beam, such that the resultant light beam received by the receiving unit has a second light intensity that differs from the first light intensity by a predetermined quantity. The optoelectronic sensor member further includes an actuator which, in response of detection of the predetermined quantity, can put the electric contact terminals in one of switch-on and switch-off states.